John Howard Northrop Biography

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World of Scientific Discovery on John Howard Northrop

Born in Yonkers, New York, Northrop received his B.S. from Columbia University in 1912, his M.A. in 1913, and Ph.D. in 1915. His desire to achieve academically is not surprising since he came from a long lineage of illustrious academics, including Princeton University President Jonathan Edwards (1703-1758) and philanthropist Frederick C. Havemeyer, who gave a chemical laboratory to Columbia University. His father, John Northrop, who was killed in a laboratory accident, was a member of the zoology department of Columbia University. His mother, Alice Belle Rich Northrop, taught botany at Hunter College.

Northrop himself is best known for his studies of enzymes and his contribution to virus research. Northrop continued the work of James B. Sumner, who had isolated and crystallized a bean protein called urease in 1926. While many researchers dismissed Sumner's work as insignificant, Northrop drew upon it to conduct his own research.

In 1930 Northrop crystallized pepsin, a digestive substance that splits proteins and is found in gastric secretions. Two years later, he crystallized trypsin, and three years after that, he crystallized chymotrypsin, both of which are protein-splitting substances found in pancreatic secretions. Because of Northrop's ability to isolate and crystallize these substances, researchers today are familiar with the proteins known as enzymes--substances that are critical for digestion, respiration, and other processes that support life.

Northrop took his theory about isolating enzymes and applied it to the isolation of the virus. He joined forces with Wendell Stanley to crystallize the tobacco mosaic virus. The result of their work was the knowledge that viruses, until then identified neither as living nor nonliving organisms, were actually nucleoproteins, nonliving compounds that consist of proteins and nucleic acids. For their work in isolating the chemical nature of enzymes and viruses, Northrop and Stanley shared the 1946 Nobel Prize in Chemistry.

In 1938 Northrop isolated the first bacterial virus, which also proved to be a nucleoprotein. He studied the intestinal bacteriophage Staphylococcus, isolating it to determine the presence of nucleic acid and protein in the virus. Today, it is known that nucleic acid is the primary part of the molecule. Northrop also introduced a purified diphtheria antitoxin in 1941. In crystalline form, he maintained it was at least forty times as effective as the more primitive antitoxin, and additionally it produced no side effects.

Northrop, who had been appointed to the staff of the Rockefeller Institute in 1916 after a stint as a captain in the Chemical War Service of the United States Army, remained a member of the Institute until his retirement in 1962. The impact of Northrop's research concerning the chemical nature of enzymes was not fully realized until subsequent research confirmed his findings nearly a decade after he received the Nobel Prize.